Fix some bugs with foveation textures;

- OpenXR only adds foveation texture when foveation is enabled.
- Render passes created for graphics pipelines include foveation info.

Author: bjornbytes

src/core/gpu.h

@@ -503,6 +503,7 @@ typedef struct {
   gpu_color_state color[4];
   uint32_t attachmentCount;
   uint32_t viewCount;
+  bool foveated;
   const char* label;
 } gpu_pipeline_info;
 

src/core/gpu_vk.c

@@ -1638,8 +1638,8 @@ bool gpu_pipeline_init_graphics(gpu_pipeline* pipeline, gpu_pipeline_info* info,
   } else {
     bool depth = info->depth.format;
     uint32_t colorCount = info->attachmentCount;
-    VkAttachmentDescription2 attachments[5];
-    VkAttachmentReference2 references[5];
+    VkAttachmentDescription2 attachments[6];
+    VkAttachmentReference2 references[6];
 
     for (uint32_t i = 0; i < colorCount; i++) {
       references[i] = (VkAttachmentReference2) {
@@ -1679,6 +1679,20 @@ bool gpu_pipeline_init_graphics(gpu_pipeline* pipeline, gpu_pipeline_info* info,
       };
     }
 
+    if (info->foveated) {
+      uint32_t index = colorCount + depth;
+
+      attachments[index] = (VkAttachmentDescription2) {
+        .sType = VK_STRUCTURE_TYPE_ATTACHMENT_DESCRIPTION_2,
+        .format = VK_FORMAT_R8G8_UNORM,
+        .samples = VK_SAMPLE_COUNT_1_BIT,
+        .loadOp = VK_ATTACHMENT_LOAD_OP_LOAD,
+        .storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE,
+        .initialLayout = VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT,
+        .finalLayout = VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT
+      };
+    }
+
     VkSubpassDescription2 subpass = {
       .sType = VK_STRUCTURE_TYPE_SUBPASS_DESCRIPTION_2,
       .viewMask = (1 << info->viewCount) - 1,
@@ -1689,7 +1703,14 @@ bool gpu_pipeline_init_graphics(gpu_pipeline* pipeline, gpu_pipeline_info* info,
 
     VkRenderPassCreateInfo2 passInfo = {
       .sType = VK_STRUCTURE_TYPE_RENDER_PASS_CREATE_INFO_2,
-      .attachmentCount = colorCount + depth,
+      .pNext = info->foveated ? &(VkRenderPassFragmentDensityMapCreateInfoEXT) {
+        .sType = VK_STRUCTURE_TYPE_RENDER_PASS_FRAGMENT_DENSITY_MAP_CREATE_INFO_EXT,
+        .fragmentDensityMapAttachment = {
+          .attachment = colorCount + depth,
+          .layout = VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT
+        }
+      } : NULL,
+      .attachmentCount = colorCount + depth + info->foveated,
       .pAttachments = attachments,
       .subpassCount = 1,
       .pSubpasses = &subpass

src/modules/graphics/graphics.c

@@ -5964,6 +5964,7 @@ void lovrPassReset(Pass* pass) {
   pass->pipeline->info.depth.format = (gpu_texture_format) (canvas->depth.texture ? canvas->depth.texture->info.format : canvas->depthFormat);
   pass->pipeline->info.multisample.count = canvas->samples;
   pass->pipeline->info.viewCount = pass->views;
+  pass->pipeline->info.foveated = canvas->foveation;
 
   pass->cameraCount = 0;
   pass->viewportCount = 0;

src/modules/headset/headset_openxr.c

@@ -3442,7 +3442,7 @@ static bool openxr_getPass(Pass** pass) {
     return true;
   }
 
-  canvas.foveation = state.swapchains[SWAPCHAIN_COLOR].foveationTextures[state.swapchains[SWAPCHAIN_COLOR].textureIndex];
+  canvas.foveation = state.foveationLevel ? state.swapchains[SWAPCHAIN_COLOR].foveationTextures[state.swapchains[SWAPCHAIN_COLOR].textureIndex] : NULL;
 
   if (!lovrPassSetCanvas(state.pass, &canvas)) {
     return false;